An electronic package is known which comprises a mounting plate, a first integrated circuit chip provided with a first optical detector, a second integrated circuit chip provided with a second optical detector and a third integrated circuit chip provided with an optical emitter, these three chips being bonded onto the mounting plate. An opaque cover is bonded onto the periphery of the mounting plate and optically isolates each of the chips because of the existence of three separate chambers. The cover has three separate openings, formed opposite the aforesaid three optical elements and provided with three transparent protective plates.